1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.widget; 18 19 import android.database.DataSetObserver; 20 import android.view.View; 21 import android.view.ViewGroup; 22 23 /** 24 * An adapter that links a {@link ExpandableListView} with the underlying 25 * data. The implementation of this interface will provide access 26 * to the data of the children (categorized by groups), and also instantiate 27 * {@link View}s for children and groups. 28 */ 29 public interface ExpandableListAdapter { 30 /** 31 * @see Adapter#registerDataSetObserver(DataSetObserver) 32 */ 33 void registerDataSetObserver(DataSetObserver observer); 34 35 /** 36 * @see Adapter#unregisterDataSetObserver(DataSetObserver) 37 */ 38 void unregisterDataSetObserver(DataSetObserver observer); 39 40 /** 41 * Gets the number of groups. 42 * 43 * @return the number of groups 44 */ 45 int getGroupCount(); 46 47 /** 48 * Gets the number of children in a specified group. 49 * 50 * @param groupPosition the position of the group for which the children 51 * count should be returned 52 * @return the children count in the specified group 53 */ 54 int getChildrenCount(int groupPosition); 55 56 /** 57 * Gets the data associated with the given group. 58 * 59 * @param groupPosition the position of the group 60 * @return the data child for the specified group 61 */ 62 Object getGroup(int groupPosition); 63 64 /** 65 * Gets the data associated with the given child within the given group. 66 * 67 * @param groupPosition the position of the group that the child resides in 68 * @param childPosition the position of the child with respect to other 69 * children in the group 70 * @return the data of the child 71 */ 72 Object getChild(int groupPosition, int childPosition); 73 74 /** 75 * Gets the ID for the group at the given position. This group ID must be 76 * unique across groups. The combined ID (see 77 * {@link #getCombinedGroupId(long)}) must be unique across ALL items 78 * (groups and all children). 79 * 80 * @param groupPosition the position of the group for which the ID is wanted 81 * @return the ID associated with the group 82 */ 83 long getGroupId(int groupPosition); 84 85 /** 86 * Gets the ID for the given child within the given group. This ID must be 87 * unique across all children within the group. The combined ID (see 88 * {@link #getCombinedChildId(long, long)}) must be unique across ALL items 89 * (groups and all children). 90 * 91 * @param groupPosition the position of the group that contains the child 92 * @param childPosition the position of the child within the group for which 93 * the ID is wanted 94 * @return the ID associated with the child 95 */ 96 long getChildId(int groupPosition, int childPosition); 97 98 /** 99 * Indicates whether the child and group IDs are stable across changes to the 100 * underlying data. 101 * 102 * @return whether or not the same ID always refers to the same object 103 * @see Adapter#hasStableIds() 104 */ 105 boolean hasStableIds(); 106 107 /** 108 * Gets a View that displays the given group. This View is only for the 109 * group--the Views for the group's children will be fetched using 110 * {@link #getChildView(int, int, boolean, View, ViewGroup)}. 111 * 112 * @param groupPosition the position of the group for which the View is 113 * returned 114 * @param isExpanded whether the group is expanded or collapsed 115 * @param convertView the old view to reuse, if possible. You should check 116 * that this view is non-null and of an appropriate type before 117 * using. If it is not possible to convert this view to display 118 * the correct data, this method can create a new view. It is not 119 * guaranteed that the convertView will have been previously 120 * created by 121 * {@link #getGroupView(int, boolean, View, ViewGroup)}. 122 * @param parent the parent that this view will eventually be attached to 123 * @return the View corresponding to the group at the specified position 124 */ 125 View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent); 126 127 /** 128 * Gets a View that displays the data for the given child within the given 129 * group. 130 * 131 * @param groupPosition the position of the group that contains the child 132 * @param childPosition the position of the child (for which the View is 133 * returned) within the group 134 * @param isLastChild Whether the child is the last child within the group 135 * @param convertView the old view to reuse, if possible. You should check 136 * that this view is non-null and of an appropriate type before 137 * using. If it is not possible to convert this view to display 138 * the correct data, this method can create a new view. It is not 139 * guaranteed that the convertView will have been previously 140 * created by 141 * {@link #getChildView(int, int, boolean, View, ViewGroup)}. 142 * @param parent the parent that this view will eventually be attached to 143 * @return the View corresponding to the child at the specified position 144 */ 145 View getChildView(int groupPosition, int childPosition, boolean isLastChild, 146 View convertView, ViewGroup parent); 147 148 /** 149 * Whether the child at the specified position is selectable. 150 * 151 * @param groupPosition the position of the group that contains the child 152 * @param childPosition the position of the child within the group 153 * @return whether the child is selectable. 154 */ 155 boolean isChildSelectable(int groupPosition, int childPosition); 156 157 /** 158 * @see ListAdapter#areAllItemsEnabled() 159 */ 160 boolean areAllItemsEnabled(); 161 162 /** 163 * @see ListAdapter#isEmpty() 164 */ 165 boolean isEmpty(); 166 167 /** 168 * Called when a group is expanded. 169 * 170 * @param groupPosition The group being expanded. 171 */ 172 void onGroupExpanded(int groupPosition); 173 174 /** 175 * Called when a group is collapsed. 176 * 177 * @param groupPosition The group being collapsed. 178 */ 179 void onGroupCollapsed(int groupPosition); 180 181 /** 182 * Gets an ID for a child that is unique across any item (either group or 183 * child) that is in this list. Expandable lists require each item (group or 184 * child) to have a unique ID among all children and groups in the list. 185 * This method is responsible for returning that unique ID given a child's 186 * ID and its group's ID. Furthermore, if {@link #hasStableIds()} is true, the 187 * returned ID must be stable as well. 188 * 189 * @param groupId The ID of the group that contains this child. 190 * @param childId The ID of the child. 191 * @return The unique (and possibly stable) ID of the child across all 192 * groups and children in this list. 193 */ 194 long getCombinedChildId(long groupId, long childId); 195 196 /** 197 * Gets an ID for a group that is unique across any item (either group or 198 * child) that is in this list. Expandable lists require each item (group or 199 * child) to have a unique ID among all children and groups in the list. 200 * This method is responsible for returning that unique ID given a group's 201 * ID. Furthermore, if {@link #hasStableIds()} is true, the returned ID must be 202 * stable as well. 203 * 204 * @param groupId The ID of the group 205 * @return The unique (and possibly stable) ID of the group across all 206 * groups and children in this list. 207 */ 208 long getCombinedGroupId(long groupId); 209 } 210
